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mmc: sdhci: unmap the bounce buffer before device release

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sdhci_allocate_bounce_buffer() allocates its buffer with devm_kmalloc()
but maps it with dma_map_single(). The buffer is therefore released by
devres without the streaming DMA mapping being unmapped.

Register a managed action after dma_map_single() succeeds so the mapping
is removed before devres releases the buffer. The action is registered
only for buffers allocated and mapped by the SDHCI core, leaving buffers
provided by host drivers under their existing ownership.

Fixes: bd9b902798 ("mmc: sdhci: Implement an SDHCI-specific bounce buffer")
Cc: stable@vger.kernel.org
Co-developed-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Myeonghun Pak <mhun512@gmail.com>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Ulf Hansson <ulfh@kernel.org>
This commit is contained in:
Myeonghun Pak
2026-07-27 23:03:22 +09:00
committed by Ulf Hansson
parent ae31bcc92b
commit 9e9f561269
1 changed files with 16 additions and 0 deletions
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16
drivers/mmc/host/sdhci.c
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@@ -4187,6 +4187,14 @@ void __sdhci_read_caps(struct sdhci_host *host, const u16 *ver,
}
EXPORT_SYMBOL_GPL(__sdhci_read_caps);
static void sdhci_unmap_bounce_buffer(void *data)
{
struct sdhci_host *host = data;
dma_unmap_single(mmc_dev(host->mmc), host->bounce_addr,
host->bounce_buffer_size, DMA_BIDIRECTIONAL);
}
static void sdhci_allocate_bounce_buffer(struct sdhci_host *host)
{
struct mmc_host *mmc = host->mmc;
@@ -4247,6 +4255,14 @@ static void sdhci_allocate_bounce_buffer(struct sdhci_host *host)
}
host->bounce_buffer_size = bounce_size;
ret = devm_add_action_or_reset(mmc_dev(mmc),
sdhci_unmap_bounce_buffer, host);
if (ret) {
devm_kfree(mmc_dev(mmc), host->bounce_buffer);
host->bounce_buffer = NULL;
host->bounce_buffer_size = 0;
return;
}
out:
/* Lie about this since we're bouncing */